Here is a C# program to read in two integers and output their sum:

namespace first
{
    using System;
    using System.Threading;
    public class SumProg
    {
        public static void Main()
        {
            Console.Write("Type in the first number: ");
            string tFirstString = Console.ReadLine();
            int tFirst = int.Parse(tFirstString);
            Console.Write("Type in the second number: ");
            string tSecondString = Console.ReadLine();
            int tSecond = int.Parse(tSecondString);
            int tSum = tFirst + tSecond;
            Console.WriteLine("The sum is " + tSum);
            Thread.Sleep(3000);     // wait for 3 seconds
        }
    }
}